Publications

Measurements of U-236 in Ancient and Modern Peat Samples and Implications for Postdepositional Migration of Fallout Radionuclides

Author(s)
Francesca Quinto, Erich Hrnecek, Michael Krachler, William Shotyk, Peter Steier, Stephan R. Winkler
Abstract

236U was analyzed in an ombrotrophic peat core representing

the last 80 years of atmospheric deposition and a minerotrophic peat

sample from the last interglacial period. The determination of 236U at levels of 107 atoms/g was possible by using ultraclean laboratory procedures and accelerator mass spectrometry. The vertical profile of the 236U/238U isotopic ratio along the ombrotrophic peat core represents the first observation of the 236U bomb peak in a terrestrial environment. A constant level of anthropogenic 236U with an average 236U/238U isotopic ratio of (1.24 ± 0.08) × 10–6 in the top layers of the core was observed. Comparing the abundances of the global fallout derived 236U and 239Pu along the peat core, the post depositional migration of plutonium clearly exceeds that of uranium. However, the cumulative 236U/239Pu

ratio of 0.62 ± 0.31 is in agreement with previous studies on the

global fallout uranium and plutonium. In the interglacial peat samples a

236U/238U isotopic ratio of (3.3 ± 0.7) × 10–12

was detected; although this measurement is an upper limit, it

constitutes a significant step forward in the experimental determination

of the natural 236U abundance and represents a true background sample for the ombrotrophic peat core.

Organisation(s)
Isotope Physics
External organisation(s)
Institute for Transuranium Elements, University of Alberta
Journal
Environmental Science & Technology
Volume
47
Pages
5243-5250
No. of pages
8
ISSN
0013-936X
DOI
https://doi.org/10.1021/es400026m
Publication date
05-2013
Peer reviewed
Yes
Austrian Fields of Science 2012
1030 Physics, Astronomy, 103031 Radiation protection, 103005 Atomic physics, 104023 Environmental chemistry
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/67c56d42-e462-4ef6-a755-9d4a4b55f1d7